One vertex per element, one color per generator, with an edge from x to x·s.
(5,6)(7,11)(8,10)(9,12)(13,14,18,22,17,21,26,28)(15,20,24,27,23,16,19,25)(1,2,3,4)(5,7)(6,9)(8,12)(10,11)(13,15)(14,16)(17,23)(18,24)(19,26)(20,21)(22,25)(27,28)(7,12)(9,11)(13,16,18,25,17,20,26,27)(14,19,22,15,21,24,28,23)(6,10)(9,11)(13,15)(14,20)(16,21)(17,23)(18,24)(19,26)(22,27)(25,28) involution — undirected(14,21)(15,23)(19,24)(22,28) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.